The Comparative Study Of XAJ Model And TOPMODEL & The Basic Frame Of Flood Forecasting System

The loss caused by flood disaster is becoming increasingly serious with the rapid development of national economy. As an important non-engineering flood protection measure, flood forecasting plays an important part in flood control. Because of the characteristic of terrain and climate, high-intensity rainstorms often happen in the Shayinghe basin located in Henan privince, and flood disasters were brought. So the Shayinghe basin is one of important flood control areas in Henan Province.The methods of extracting basin network and topographic index from DEM were discussed. Then the network and the topographic index were extracted from the 25×25 DEM of Zhongtang basin, the extracted river network and the actual network basically approaches. The XAJ model and TOPMODEL were applied to the Zhongtang basin, the error of calculated results was evaluated and the reasons of causing error were analyzed, then the same and difference of the two models was discussed. From the comparative analysis of the application of the two models, it could be found that the two models, that both based on the saturation excess mechanism, applied well in Zhongtang Basin. So they could be applied to the flood forecasting in this basin. The relationship between the distribution of topographic index and the tension water capacity curve was researched. The tension water capacity curve gotten form topographic index fitted well with that calculated by XAJ model.As the platform for forecasters, flood forecasting system can effectively improve the quality and efficiency of forecasts. After presenting the components and corresponding functions of flood forecasting system, the flood forecasting system of Shayinghe basin was constructed. The simulations of daily flow and event floods in the areas before the Luohe section in Shayinghe basin were carried by the soft, which was programmed for parameters calibrating of XAJ model. Then the parameters, which adopted to the ten subbasins of Ziluoshan, Ruzhou, Dachen, Zhaopingtai, Baiguishan, Gushitan, Guanzhai, Hekou, Mawan, Luohe, were calculated. It showed that the sequential simulation and the event simulation both fitted well to observations according to analysis of errors. It could be concluded that XAJ Model can be applied to the flood forecasting system of Shayinghe Basin.